What is 440C Stainless Steel?. ASTM A276 standard grade 440c stainless steel is a high carbon martensitic stainless steel, which is generally supplied in the annealed condition with a maximum Brinell hardness of 269 (Rc29) or annealed and cold drawn with a maximum Brinell hardness of 285 (Rc31).. AISI 440C steel is characterized by good corrosion resistance in mild domestic and industrial ...